1. Technical Field
The subject matter disclosed herein relates generally to appliances and, more particularly, to an induction heating system that is configured to vary the power density profile for heating electrically conductive objects.
2. Description of Related Art
Induction heating is a method of heating an electrically conductive load using an alternating magnetic field to induce currents in the load. Induction heating is beneficial in applications where direct contact with a load is undesired or unattainable. This method is also efficient because the majority of heating energy appears directly within the load.
Induction cooking systems work according to the principle of electromagnetic induction. These systems are configured to induce an eddy current into the base of an electrically conductive cooking vessel, such as a pan, pot, or skillet. Heat is generated because the cooking vessel exhibits resistance to the induced eddy currents.
In many systems the eddy currents are induced by a coil or ring placed beneath the cooking vessel. Alternating current (AC) input is supplied to the coil such as by an inverter, which is configured to provide the AC input at, but not limited to, a frequency of 20 kilohertz or greater. A magnetic field is generated by the AC current in the coil. The magnetic field induces the eddy currents that flow in the base of the cooking vessel. Food and/or water is heated conductively by the heated cooking vessel.
Conventional induction cooking systems often utilize a single wound ring or discrete groupings of wound rings to generate the magnetic field. These configurations limit the extent to which the resulting power density profile can vary. When constructed of the single wound ring, for example, the power density profile is generally fixed by the spacing and configuration of the concentric windings of the wound rings. Similar limitations also affect the induction cooking systems that use discrete groupings. Although the power density profile can vary in accordance with the collective manipulation of the discrete groups, the induction cooking system is still effectively restricted to the power density profiles that are effectuated by the configuration of the groupings of the heating device.